The study compared the antibacterial effect of crude Patani leaf extract (PLE) with commercially available antibiotics (Penicillin G) and (Streptomycin) and identified the most effective concentration capable of inhibiting the growth of Staphylococcus aureus and Escherichia coli It was laid out following the Factorial in Completely Randomized Design with five treatments replicated three times.

The study was conducted in two sets: Staphylococcus aureus was used as the test organism with (Peniciilin G) as control. The treatments were designated as follows: Treatment 1 (Pen G), Treatment 2 (25% PLE), Treatment 3 (50% PLE), Treatment 4 (75% PLE), and Treatment 5 (100% PLE). The second set used (Streptomycin) as control and Escherichia coli as the test organism with the used of Patani leaf extract in varying doses of concentrations as follows: 25%, 50%, 75%, and 100%.

Zone of inhibition after 12 hours of incubation of Staphylococcus aureus showed that T3, T4, T5 exhibited moderate antibacterial efficacy and are comparable to each other. No zone of inhibition noted in T2 (25% Leaf extract) throughout the 36-hour duration of the study. After 24 to 36 hours of incubation T3 (50% Leaf extract) continue to have better degree of antimicrobial efficacy as compared with that of T4 and T5. The descending zone of inhibition obtained from T4, and T5 might be due to the difficulty ofthe crude extract to diffuse through the agar.

In the study using the Escherichia coli, patani leaf extract at different concentrations after varying hours of incubation did not exhibit any significant effect on the bacterial growth as the Escherichia coli colonies formed around close to the patani leaf extract sample disks. No zones of inhibition were observed in these treatments except for the positive control.

The result of the study revealed a certain degree of antimicrobial efficacy of patani leaf extract against Staphylococcus aureus but not against gram negative Escherichia coli. Fifty percent (50%) dilution of the patani extract proved to be the optimum concentration that best inhibits staphylococci growth using agar diffusion test. However, it is not comparable to that observed in the commercially available antibiotic positive control treatment.

Thesis (Doctor of Veterinary Medicine)

Includes appendices and bibliographical references.